Summary of Work: Human airway epithelial cells lining the conduction airways produce Clara cell secretory protein (CCSP). This protein is an inhibitor of Phospholipase A2 and has other immunomodulatory properties. A human airway bronchial epithelial cell line has been found to express mRNA for CCSP and to produce and secrete CCSR CCSP secretion and levels of steady-state CCSP mRNA were altered by treatment of these human airway epithelial cells with interferon-gamma in a time- and dose- dependent fashion.